Hot melt adhesive material dispensing systems must be operated intermittently in order to, for example, only deposit the hot melt adhesive material upon predetermined regions of substrates, at predetermined times, so as not to cause operational problems or to result in undesirable product characteristics, and concomitantly, to control the flow of the hot melt adhesive material during those periods of time when the hot melt adhesive material is not actually being dispensed. Adhesive control module assemblies, having suitable nozzle dispensing valve assemblies incorporated therein, are conventionally used to effectively control the starting and stopping of the flow of the hot melt adhesive material to the dispensing nozzle and its associated discharge orifice. The nozzle dispensing valve assemblies each comprise a forwardly disposed nozzle dispensing valve member, a valve stem, and a piston member integrally mounted upon a rearward portion of the valve stem for disposition within an air cylinder chamber. Accordingly, when control air is selectively supplied into the opposite ends of the air cylinder chamber, the piston member will be appropriately actuated or moved so as to, in turn, appropriately actuate or move the nozzle dispensing valve between its OPENED, unseated position and its CLOSED, seated position in order to control the intermittent dispensing of the hot melt adhesive material. Still yet further, solenoid control valve assemblies are operatively associated with the adhesive control module assemblies for controlling the routing of the control air into and out of the air cylinder chamber in order to, in fact, control the movements of the piston member within the air cylinder chamber.
In accordance with one conventional type of system, the solenoid control valve assemblies are operatively connected to the adhesive control module assemblies by means of suitable fittings and connecting tubes. The connecting tubes effectively reduce the amount of heat that tends to be transferred from the adhesive control module assemblies to the solenoid control valve assemblies, which results in enhancing the service life of the solenoid control valve assemblies, however, the operative connection of the solenoid control valve assemblies to the adhesive control module assemblies by means of the connecting tubes also increases the length of the fluid path through which the control air must travel between the solenoid control valve assemblies and the adhesive control module assemblies. Accordingly, the actuation, cycling, or response times, attendant the switchover operations effectuated by means of the solenoid control valve assemblies, are relatively slow. In order to rectify the operative deficiencies of the aforenoted conventional type of hot melt adhesive material control system, a second conventional type of system was developed, as is illustrated within FIG. 1, wherein the solenoid control valve assembly is adapted to be mounted upon the adhesive control module assembly thereby eliminating the need for the connecting tubes.
More particularly, as can be appreciated from FIG. 1, an adhesive control module assembly is disclosed at 12 and is disposed atop a dispensing nozzle assembly 14. A solenoid control valve assembly 16 is disposed above the adhesive control module assembly 12, and an adapter 18 is interposed between the solenoid control valve assembly 16 and the adhesive control module assembly 12. A first heat isolator 20 is interposed between the upper surface portion of the adaptor 18 and the undersurface portion of the solenoid control valve assembly 16, and a second heat isolator 22 is interposed between the upper surface portion of the adhesive control module assembly 12 and the undersurface portion of the adaptor 18. Still yet further, an inlet or supply port 24 for supplying control air to the solenoid control valve assembly 16 is provided within a first side wall portion of the adaptor 18, while an outlet or exhaust port 26 for exhausting the control air from the solenoid control valve assembly 16 is provided within a second oppositely disposed side wall portion of the adaptor 18. Accordingly, it can be appreciated that the control air is conducted into the adaptor 18 by means of the inlet or supply port 24, routed upwardly into the solenoid control valve assembly 16 so that the solenoid control valve assembly 16 can properly route the control air downwardly through the adaptor 18 to the appropriate side of the piston member of the nozzle dispensing valve assembly disposed within in the adhesive control module assembly 12 in order to appropriately move the piston member and thereby control the disposition of the nozzle dispensing valve member of the adhesive control module assembly 12, and concomitantly therewith, the air, disposed upon the opposite side of the piston member of the nozzle dispensing valve assembly can be routed upwardly through the adaptor 18, into the solenoid control valve assembly 16, and back down into the adaptor 18 for discharge outwardly through or from the outlet or exhaust port 26. It can therefore be appreciated that while the solenoid control valve assembly 16 is mounted upon the adhesive control module assembly 12 without the use of interconnecting tubes, it is nevertheless seen, and to be appreciated, that the fluid flow pathway for the control air is quite circuitous and therefore still relatively long whereby, again, the actuation, cycling, or response times attendant the switchover operations effectuated by means of the solenoid control valve assembly 16, will still be relatively slow. In addition, the definition or formation of the various fluid passageways within the adhesive control module assembly 12 and within the solenoid control valve assembly 16 are relatively complex so as to require extensive machining operations.
A need therefore exists in the art for a new and improved hot melt adhesive material dispensing system comprising a new and improved solenoid control valve assembly, for use in connection with an adhesive control module assembly, wherein the new and improved solenoid control valve assembly is to be directly mounted upon the adhesive control module assembly so as to eliminate the connecting tubes between the solenoid control valve assembly and the adhesive control module assembly, wherein the incoming and outgoing control air flow paths can be defined within the solenoid control valve assembly, and within fittings thereof which are adapted to mate with bores defined within the adhesive control module assembly, so as to effectively comprise substantially short linear fluid flow paths between the solenoid control valve assembly and the adhesive control module assembly in order to thereby minimize the lengths of the control air flow paths extending between the solenoid control valve assembly and the adhesive control module assembly, and wherein further, the fittings of the solenoid control valve assembly can enable the quick and easy removal and replacement of the solenoid control valve assembly from and upon the adhesive control module assembly.